1. Field of the Invention
The present invention relates to a camera using a so-called electro-developing recording medium, in which an image obtained by exposing the recording medium is electronically developed.
2. Description of the Related Art
Conventionally, there is known a photographic material which electronically develops an optical image formed thereon through a photographing lens. U.S. Pat. No. 5,424,156 (corresponding to Japanese Unexamined Patent Publication No. 5-2280), for example, discloses a recording medium which is a combination of an electrostatic information recording medium and an electric charge keeping medium. In this specification, such a recording medium is referred to as an electro-developing recording medium, and a camera using the electro-developing recording medium is referred to as an electro-developing type camera.
In the electro-developing recording medium disclosed in the above publication, the electrostatic information recording medium has a photoconducting layer and an inorganic oxide material layer, and the electric charge keeping medium has a liquid crystal display. In this structure, when the electrostatic information recording medium is exposed while an electric voltage is applied to the electrostatic information recording medium and the electric charge keeping medium, electric charge in accordance with the amount of incident light is generated in the electrostatic information recording medium. Since the intensity of the electric field applied to the liquid crystal display facing the electrostatic information recording medium is varied in accordance with the generated electric charge, an image corresponding to the amount of light distribution is indicated or developed on the liquid crystal display.
The image developed on the liquid crystal display can be sensed by using an optical element such as a line sensor. Namely, a front surface of the electro-developing recording medium is illuminated by light, and the light passing through the recording medium is sensed by the line sensor which scans along the rear surface of the recording medium, so that the image can be read out from the line sensor.
If the electro-developing type camera is constructed in such a manner that, in addition to the photographing operation, the image can be read out from the electro-developing recording medium, then a member such as an illumination light source needs to be disposed between the photographing optical system and the electro-developing recording medium. This structure causes difficulty in reducing the axial size of the photographing optical system, so that a design restriction occurs.